/*
 * Copyright 2008 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.user.client.rpc.impl;

import cc.alcina.framework.common.client.util.CommonUtils;

import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsArrayInteger;
import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.UnsafeNativeLong;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException;
import com.google.gwt.user.client.rpc.SerializationException;
import com.google.gwt.user.client.rpc.impl.AsyncDeserializer;
import com.google.gwt.user.client.rpc.impl.Serializer;
import com.google.gwt.core.client.GwtScriptOnly;

/**
 * For internal use only. Used for server call serialization.
 */
@GwtScriptOnly
public final class ClientSerializationStreamReader extends
		AbstractSerializationStreamReader {
	
	private static native JavaScriptObject eval(String encoded) /*-{
		return eval(encoded);
	}-*/;

	private static native int getLength(JavaScriptObject array) /*-{
		return array.length;
	}-*/;

	int index;

	private JavaScriptObject results;

	private JavaScriptObject stringTable;

	private JsArrayInteger typeTable;

	Serializer serializer;

	public ClientSerializationStreamReader(Serializer serializer) {
		this.serializer = serializer;
	}

	private static final int SERIALIZATION_STREAM_VERSION = 1007;

	@Override
	public void prepareToRead(String encoded) throws SerializationException {
		results = eval(encoded);
		index = getLength(results);
		super.prepareToRead(encoded);
		if (getVersion() != SERIALIZATION_STREAM_VERSION) {
			throw new IncompatibleRemoteServiceException("Expecting version "
					+ SERIALIZATION_STREAM_VERSION + " from server, got "
					+ getVersion() + ".");
		}
		if (!areFlagsValid()) {
			throw new IncompatibleRemoteServiceException(
					"Got an unknown flag from " + "server: " + getFlags());
		}
		stringTable = readJavaScriptObject();
		typeTable = (JsArrayInteger) readJavaScriptObject();
	}

	public void doDeserialize(AsyncCallback postPrepareCallback) {
		this.postPrepareCallback = postPrepareCallback;
		Scheduler.get().scheduleIncremental(new AsyncDeserializer(this));
	}

	AsyncCallback postPrepareCallback;

	@Override
	public Object readObject() throws SerializationException {
		// at the end of the deserialization, return root
		if (index == 0) {
			return seenArray.get(0);
		}
		return super.readObject();
	}

	public native boolean readBoolean() /*-{
		return !!this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native byte readByte() /*-{
		return this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native char readChar() /*-{
		return this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native double readDouble() /*-{
		return this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native float readFloat() /*-{
		return this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public native int readInt() /*-{
		return this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	@UnsafeNativeLong
	public native long readLong() /*-{
		var s = this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
		return @com.google.gwt.lang.LongLib::longFromBase64(Ljava/lang/String;)(s);
	}-*/;

	public native short readShort() /*-{
		return this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public String readString() {
		return getString(readInt());
	}

	@Override
	protected Object deserialize(String typeSignature)
			throws SerializationException {
		int id = reserveDecodedObjectIndex();
		Object instance = serializer.instantiate(this, typeSignature);
		rememberDecodedObject(id, instance);
		serializer.deserialize(this, instance, typeSignature);
		return instance;
	}

	@Override
	protected native String getString(int index) /*-{
		// index is 1-based
		return index > 0 ? this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::stringTable[index - 1]
				: null;
	}-*/;

	private native JavaScriptObject readJavaScriptObject() /*-{
		return this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::results[--this.@com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader::index];
	}-*/;

	public int getTypeId(int index) {
		return typeTable.get(index);
	}

	public int getTypeTableLength() {
		return typeTable.length();
	}
}
